btrfs: Don't panic when we can't find a root key

When we failed to find a root key in btrfs_update_root(), we just panic.

That's definitely not cool, fix it by outputting an unique error
message, aborting current transaction and return -EUCLEAN. This should
not normally happen as the root has been used by the callers in some
way.

Reviewed-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

1 files changed, 8 insertions, 5 deletions

diff --git a/fs/btrfs/root-tree.c b/fs/btrfs/root-tree.c
index 893d12fbfda0..1b9a5d0de139 100644
--- a/fs/btrfs/root-tree.c
+++ b/fs/btrfs/root-tree.c
@@ -137,11 +137,14 @@ int btrfs_update_root(struct btrfs_trans_handle *trans, struct btrfs_root
                 goto out;
         }
 
-        if (ret != 0) {
-                btrfs_print_leaf(path->nodes[0]);
-                btrfs_crit(fs_info, "unable to update root key %llu %u %llu",
-                           key->objectid, key->type, key->offset);
-                BUG_ON(1);
+        if (ret > 0) {
+                btrfs_crit(fs_info,
+                        "unable to find root key (%llu %u %llu) in tree %llu",
+                        key->objectid, key->type, key->offset,
+                        root->root_key.objectid);
+                ret = -EUCLEAN;
+                btrfs_abort_transaction(trans, ret);
+                goto out;
         }
 
         l = path->nodes[0];